These
Level Sets include a great variety of levels. Some may have
levels that are extremely difficult, some may finish themselves with no user interaction, and some may have dozens of rings on a single level.

This set was made during the early days of Ricochet Infinity, and removed after the game was released to fix some bugs. If you haven't seen it already, there might be some nice surprises. If you've played it earlier, there isn't much of a difference.